(1) Field of the Invention
This invention is related to magnetic recording heads and, more particularly, to shielding of perpendicular magnetic recording heads.
(2) Description of the Related Art
In order to push for high track density perpendicular magnetic recording (PMR), it is necessary to have side shield PMR design to reduce fringe and to improve side erasure. There are several proposals to use subtractive methods such as reactive ion etching (RIE) or ion beam etching (IBE) to etch into the magnetic shield followed by atomic layer deposition (ALD), plating, and chemical mechanical polishing (CMP) methods to form side shield PMR. However, all these proposals do not have a self-aligned structure between the side shield and the trailing shield.
U.S. Pat. No. 7,002,775 to Hsu et al discloses side and trailing shields, but provides no details about how they are made. U.S. Pat. No. 7,253,991 to Fontana, Jr. et al teaches side and trailing shields formed by CMP, but they are not self-aligned. U.S. Pat. No. 7,068,453 to Terris al el and U.S. Patent Application 2007/0253107 to Mochizuli et al teach that side and trailing shields may be a single piece or they may be separate pieces. U.S. Pat. No. 7,070,698 to Le shows side shields and trailing shields formed separately. Co-pending U.S. Patent Application 2007/0177301 to Han et al, filed on Feb. 2, 2006, discloses a method of forming side shields where the pole tip is aligned to the side shields and then forming an upper shield over the side shields.
U.S. Patent Applications 2007/0186408 to Nix et al and 2006/0044682 to Le et al teach self-aligned wrap-around side and trailing shields. However, the main pole in these inventions is formed by deposition and etching processes.
In co-pending patent application Ser. No. 11/906,717 (HT07-016) filed on Oct. 3, 2007, a method is proposed to make a self-aligned full side shield PMR. FIG. 1 shows the air-bearing surface (ABS) view of this self-aligned full side shield PMR head. Main pole 16 is surrounded by write gap 24. Self-aligned full side shield 26 surrounds the pole. Trailing shield 28 overlies the side shield. However, using two separate processes to fabricate the side shield and the trailing shield creates interface flux choking at the interface between the side and trailing shields. Adjacent track erasure (ATE) problems were observed due to this flux choking.